Phys Eco Exam 2 Section 3: Thermoregulation & Heat Exchange

Why are warm-blooded and cold-blooded poor physiological terms?

They do not adequately distinguish heat source from body-temperature stability.

What is endothermy?

Relying primarily on internally produced metabolic heat.

What is ectothermy?

Relying primarily on environmental heat sources.

What is homeothermy?

Maintaining a relatively stable body temperature.

What is poikilothermy?

Having a body temperature that varies.

What is heterothermy?

A regulated state in which body temperature is allowed to vary.

Do endotherms and ectotherms obtain heat exclusively from one source?

No. All animals produce internal heat and obtain some heat from their environment.

What is temperature?

Average kinetic energy of molecules.

What is heat?

Total amount of kinetic energy in molecules.

What determines heat exchange?

Temperature differences.

What is thermoregulation?

Behavioral or physiological manipulation of heat exchange with the environment.

What are the four avenues of heat exchange?

Conduction, convection, radiation, and evaporation.

What is conduction?

Direct heat flow between two solid materials in contact.

What is convection?

Heat exchange through movement of gas or liquid across an animal's surface.

What factors affect heat-flow rate?

Temperature difference, contact area, conductive properties, and fluid movement.

What is solar radiation?

Radiant energy absorbed from the sun.

What is thermal radiation?

Radiation emitted by objects above absolute zero.

What is evaporation?

Liquid water becoming vapor, causing heat loss.

Can evaporation cause heat gain?

No. Evaporation always causes heat loss.

What does insulation do?

Reduces heat exchange between an animal and the environment.

Why is still air important for insulation?

Still air is an excellent insulator.

Which works better, external or internal insulation?

External insulation, such as fur or feathers, works better than internal insulation such as body fat.